1. Field of the Invention
The present invention relates to connectors for use in forming railings made with treated lumber and tubular metal balusters wherein the balusters are isolated from corrosion by the lumber.
2. Brief Description of the Prior Art
It has been found that an attractive fence or railing resembling a wrought iron fence can be made with hollow metal balusters mounted in holes drilled in top and bottom wood rails. One such construction is described in U.S. Pat. No. 6,394,422 to Jones et al. which is incorporated by reference herein.
In recent years there has been a change in the chemicals employed for treating lumber used outside. Arsenic, the primary component used to preserve wood from deterioration, in the form of copper chromated arsenic (CCA), has been banned. Newly developed arsenic free treatments include alkaline copper quaternary (ACQ) and copper azole (CA). These treatments, however, contain approximately six times more copper than CCA.
Galvanic corrosion occurs when dissimilar metals are in contact with each other in the presence of an electrolyte. The increased copper content in new wood preservatives has caused metal balusters when formed of aluminum to corrode, especially at the point of contact with the wood. The problem of corrosion is increased in an outdoor environment where the components are exposed to moisture, i.e., from rain, dew and other sources.
Metal balusters formed of aluminum are painted. It has been found that the alkaline in the ACQ is used as a paint remover. Hence ACQ may be expected to corrode the paint as well as cause galvanic corrosion of the aluminum of metal balusters in contact with wood treated with ACQ.
U.S. Pat. Nos. 1,797,883, 3,810,341, 4,403,767, 4,886,245, 5,419,538, 5,474,395, 6,126,148, 6,305,670, 6,308,937, 6,311,957, and 6,394,422 are incorporated by reference herein.